By Sophie Herdman TV.BT
When Lewis stars Kevin Whately and Laurence Fox announced they were taking a year out from the show, rumours started flying that instead of a sabbatical, it could be the end.
It was a gloomy prospect for Lewis fans who found comfort in the show following the demise of the original Inspector Morse series.
But back at the start of last year, there was a glimmer of hope in the form of a pilot show called Endeavour.
It marked the 25th anniversary of the first Morse episode and told the story of Morse as a young detective in the 1960s who was known by his first name, Endeavour.
The pilot was a huge hit, scoring exceptional viewing figures. As a result, more than a year later, Endeavour is returning to our screens for a four-episode series.
The stars of the new show - Shaun Evans, who plays Endeavour Morse, and Roger Allam, who takes the role of his mentor, Detective Inspector Fred Thursday - are in a light-hearted mood as they explain how they created their on-screen relationship.
Asked if they took part in bonding exercises, they giggle like a pair of naughty schoolboys and Shaun quips: "Oh yeah, there was that one in the sauna."
Roger chips in: "And there's the dancing exercise. It's nice to see panic in the director's eyes when we say we like to do the scene first as expressive dance."
They are joking, of course, but soon the pair switch to serious conversation, discussing how they prepared to take on such a beloved British institution.
Big shoes to fill
"I had never watched the show," Shaun admits. He focused instead on reading the books, aware that an impersonation of John Thaw, the original Inspector Morse, was the last thing that was wanted.
"When I first got the job I very specifically said that it had to move forward. I said if they want someone to do an impression of anything that's gone before they should look elsewhere. But it seemed we all wanted the same thing," explains the 33-year-old Liverpudlian actor.
That's why, while Endeavour might reference old Morse and his penchant for cryptic crosswords, classical music and a pint of ale, the character actually feels novel and fresh.
Each episode of the new series is filmed by a different director. While some actors might have found such diversity challenging, Shaun and Roger agree it was a positive.
"It made it exciting," says Shaun. "There's no room for complacency, each came in and tried to better the latter. It's a great atmosphere to work in."
Roger was more familiar with Morse than his co-star. In fact, he appeared on the other side of the law in one of the original Inspector Morse episodes.
"I guested in a Morse in 19 hundred and never you mind. I also used to watch it when it first came out," says Roger, 59.
With such a successful pilot, it seems a no-brainer that the show will win a big audience. But after 13 years of Inspector Morse and seven series of Lewis, there's always the risk that TV viewers might have Morse fatigue. Shaun and Roger don't seem concerned, however.
"There's a big hunger for something that straddles Sunday evening," says Roger. "Something that's an exciting, interesting and well put together feature-length."
All of the scripts were passed by Colin Dexter, author of the original Inspector Morse novels, before filming.
"I don't think it's a contract thing, it's a courtesy thing," says Shaun. "It's right because the nucleus of the characters came from him - no one else knows them so well."
If you watch closely you might spot Dexter in the background - he features as an extra in each episode.
And if you've got a particularly good eye for faces, you might also spot John Thaw's daughter, Abigail Thaw, who plays the editor of the Oxford Mail.
And of course this wouldn't be a real Morse show without the traditional Oxford setting. "It's a beautiful place," says Shaun, "but also with the architecture and the people that populate it, it all clicks into place, it's such a specific part of these stories."
Endeavour continues on Sunday nights on ITV